Rote Fahrwassertonne auf der Elbe mit einem Containerschiff im Hintergrund
Under water

The Elbe: A river in the rhythm of the tides

The difference in water level between high and low tide in the Port of Hamburg is approximately 3.80 meters. We experience this tidal range on the Elbe several times a day. This process moves large amounts of sand and silt, which settle in the navigation channel and in the port.

Eine Pegellatte mit der Nummer 121 auf einem Dalben an der Elbe, im Hintergrund ein Ufer mit Steinen und Bäumen
Level gauge for measuring the water level at the entrance to the Harburg harbor lock. In Hamburg, the difference between high and low tide is currently 3.83 meters on average.

The Elbe is not a long, calm river here. On the contrary: the influence of the North Sea reaches far inland here. From the mouth in Cuxhaven to the weir in Geesthacht, the Elbe is subject to the fluctuations of the tides. This 160 km long section is therefore also known as the Tidal Elbe. 

On this stretch, the river experiences a considerable difference between high and low water every six hours due to the tide, which is currently 3.83 m in Hamburg. This means that the Elbe is constantly in motion here. When the tide changes, large forces are at work under the surface of the water. The current causes a suction at the bottom and pulls natural components such as sand and silt with it - first in one direction, then in the other. However, these movements are not uniform, but are usually stronger from the sea side. The tide, which pushes the water inland, almost always has more force and pumps more silty material upstream than is washed back into the North Sea at low tide. This effect, which occurs in many estuaries around the world, is also known as "tidal pumping" and is all the stronger the less water flows down the Elbe, for example when the summers are very dry.

The stronger tidal current pumps more muddy material towards the harbor than is washed back towards the North Sea at low tide.
"Tidal pumping": The forces of ebb and flow act like a pump in the tidal Elbe.

The tidal Elbe is therefore a dynamic system. Between the tides, when the current subsides a little, the particles sink to the bottom as so-called sediments. This creates new mudflats or elevations under water, which in turn influences the currents in the Elbe. Sediments are deposited particularly in places where the water flow velocity is already lower, such as in the harbor basin and side arms, causing these areas to silt up. Both the harbor basin and the fairway must therefore be regularly cleared of the accumulations of sand, silt and suspended matter, otherwise the Elbe will eventually no longer be passable for larger ships.

Luftbild von Priel und Schilfguertel im Suesswasserwatt der Elbe bei Ebbe, Elbinsel Bishorster Sand
Suspended matter and sediments are transported by the currents in the Elbe, which then settle again in areas where the currents are calm.
Regular dredging is the only way to maintain the required water depths in Hamburg and the Tidal Elbe. Just like in many other ports around the world.

Two impressive videos by aquadot show the changing tides from a bird's eye view.

By the way, we publish the exact parameters of the tides in Hamburg every year in the "Water Resources Information".

 

FAQ on the tides of the Elbe in Hamburg

The most important questions and answers at a glance.

 

The Elbe in Hamburg is subject to the tides of the North Sea. The difference in height between high and low tide in the Port of Hamburg is currently around 3.80 meters, which means that the water level and current change significantly several times a day. This has an impact on the transport and displacement of suspended matter and sediment as well as shipping traffic, for example.</p

 

 

The influence of the tides extends from the estuary near Cuxhaven to the weir in Geesthacht. This approximately 160-kilometre-long section is also known as the Tidal Elbe or Elbe estuary.</p

 

 

Large quantities of sand and silt are moved by the ebb and flow of the tide. The stronger tidal current transports more sediment upstream towards the harbor than is carried back towards the North Sea at low tide ("tidal pumping").</p

 

 

In the tidal cycle, the current decreases at times (capsize points), causing suspended matter to settle as sediment - especially in current-calmed harbor basins and side arms. As a result these areas become silted up, which is why the fairway and harbor have to be dredged regularly.</p

 

Back to overview

Weitere Artikel

Kinderbeine und Füsse in roten Gummistiefeln und eine gelbe Spielplatzschaufel im Schlick
Under water

Playground quality: The Elbschlick in Hamburg is better than its reputation

The Elbe hasn't always had the best reputation when it comes to water quality—in the past, many pollutants were discharged into the river. In Hamburg, the river's final stop before the North Sea, contaminated sediments accumulated. But times have changed.

Read more
A hand with purple gloves takes a sediment sample from a body of water with a small spoon
Under water

Sand, silt, mud, silt - a brief history of sediments

The Elbe is subject to currents flowing from two directions: the upper reaches of the river and the sea. While the upper reaches of the Elbe carry suspended matter toward the harbor, the incoming tide washes sandier material from the North Sea into the city. In the harbor, the particles settle to…

Read more